#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>

int main(int argc, char **argv)
{
	int fd;
	int val;
	char *p = "/dev/first_dev";
	fd = open(p, O_RDWR);
	
	if (fd < 0) {
		printf("can't open %s\n", p);
	}
	
	if (argc != 2) {
		printf("Usage :\n");
		printf("%s <on|off>\n", argv[0]);
		return 0;
	}

	if (strcmp(argv[1], "on") == 0) {
		val = 1;
	} else {
		val = 0;
	}

	write(fd, &val, 4);

	return 0;
}

